(For a refresher on stickleback and what I’m doing to them, read this.)
Here is what stickleback nesting behaviour looks like:
This is a benthic male (in the “wrong” habitat, you’ll notice) tending a nest that has eggs in it. He fans them to circulate oxygenated water over them, he touches up the outside of the nest, and he rubs his body along it to deposit spiggin, which holds it together. Sometimes he’ll also swim through the nest, which gets spiggin on the inside as well. I haven’t managed to get a video of this yet.
The eggs in this nest were freshly laid, so this male is still in courtship mode, and would be a for a few days—he will try to mate with multiple females until the eggs are old enough and he switches into parental mode.
Here’s a closer look at the nest, which, yes, I destroyed after the experimental trial. The top matches the pond bottom well:
In the wild, after they hatch, stickleback fry sit on the bottom for a week with their father guarding them. Then they’ll fill their swim bladders with air and become able to control their buoyancy. They’ll stay in a little shoal around the nest for up to a few weeks under the watchful eyes of stickledad. Later they’ll mingle with juveniles from other families as they feed and grow, while their father, if he’s survived, will try to nest again.